Are your friends destroying your diet?

By Ali Eaves

Beware of your friend who likes to supersize their combo platters. Peer pressure may be to blame for your lack of control when ordering out, according to a new study from the University of Illinois.

Researchers analyzed a restaurant’s lunch receipts over a 19-week period and found that people who dine in groups tend to order from the same menu category—like salads, burgers, or pasta—when eating together. In addition, it was found that calorie counts on menus were less influential than your buddies when it comes to picking a healthy meal.

It’s as simple as not wanting to stray too far from the social norms of the group. “Generally, we’re happier doing what our friends are doing,” says study author Dr Brenna Ellison. So if your friend orders an extra scoop of ice cream, emotionally you'll feel better if you do the same. (Here's how to lose weight while cheating on your diet.)

This social influence holds true even when you eat alone, according to a separate review in the Journal of the Academy of Nutrition and Dietetics. If you’re aware that others are eating large portions or higher-calorie foods, it increases the odds that you’ll make similar choices. The good news is it can work both ways: If your friend orders a salad, it might encourage you to order something similar.

So what can you do to stay in control of your diet—short of ditching your friends every time they want to hit the all-you-can-eat?

Try ordering first to set the tone for the table, says Ellison. If you’re worried about peer pressure, make things easier on yourself by suggesting a restaurant that has a healthier menu to begin with before the group decides on where to go. And if all else fails, use this workout to triple your metabolism.